Self-laying track



Jan. l0, 1950 c. o. sLEMMoNs sELF-LAYING TRACK Filed Nov. 11,l 1944 3 Sheets-Sheet l Jan. l0, 1950 c. o. sLEMMoNs sELF-LAYING mex 3 Sheets-Sheetv 2 Filed Nav. 11', 1944 HUET-22h51.. [has/e5 7E/Emmas Jan. l0, 1950 v c. o. sLEMMoNssELF-LAYING TRACK 3 Sheets-Sheet 3 Filed Nov. 11, ""44:

ily; l. i?? n. Tmmw Patented Jan. l0, 1950 SELF-LAYING TRACK Charles 0. Slemmons, Akron, Ohio, assignor to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Appueatien November 11, 1944, serial No. "ssasss (ci. aos-1o) 20 Claims. l

This invention relates to track for self-laying track type vehicles and is especially useful on vehicles to be operated over ice and snow. 'Ihis application is a continuation-impart of my application Serial No. 500,517 led Aug. 30, 1943 entitled Self-laying track, now abandoned.

Objects of the invention are to provide a high degree of dotation over soft snow or mud, to provide traction, to provide high resistance to adhesion of ice and snow, to provide high resistance to wear, to provide traction on hard ice, to provide resilient connection of the shoes and the cables, to provide great transverse stability with shoesl of broad lateral extent and light weight, to provide light weight, and to provide facility of construction and repair.

A further object is to provide for increased resistance to lateral twisting or bending while nevertheless maintaining good longitudinal ilexibility.

These and other objects will appear from the following description and the accompanying drawings.

Of the drawings,

Fig. 1 is a perspective view of part of a vehicle with tracks thereon made in accordance with and embodying the invention,

Fig. 2 is a plan view showing the driving face of a portion of the track,

Fig. 3 is a sectional view thereof taken on line 3-3 of Fig. 2,

Fig. 4 is a sectional view thereof taken on line 4-4 of Fig. 2,

Fig. 5 is a sectional view thereof taken on line 5-5 of Fig. 2,

Fig. 6 is a plan view showing the driving face of a portion of a modied embodiment of the invention,

Figure 7 is a sectional view thereof taken on line I--l of Fig. 6,

Fig. 8 is a sectional view thereof taken on line 8 8 ofFig. 6,

Fig. 9 is a sectional view thereof taken on line 9-9 of Fig. 6,

Fig. 10 is a side elevation of a portion of a further modifled form of the invention, parts being broken away, showing one of the driving and guiding wheels and one of the load carrying wheels,

Fig. l1 is a plan view of a portion of the track thereof looking at the sprocket engaging face,

Fig. 12 is a perspective view of a band member therefor, shown partly in section,

Fig. 13 is a longitudinal sectional view thereof, taken on line I3--I 3 of Fig. 11, and

Fig. 14 is a sectional view thereof taken on line I4-I4 ofFig. 2. the load-carrying wheels being indicated in dot and dash lines.

In accordance with the invention a pair of bands of resilient rubber-like material, each enclosing tension elements or members, are held in parallel spaced-apart relation by guiding and driving members assembled with and secured to' cross members which may be in the form vof metal plates or straps embedded in the bands, the bands acting to support the bogie wheels of the vehicle and provide tracks therefor, and also assembled with and secured to flotation members or structures adapted to supply broad tread, areas for supporty on snow, sand, or mud. These flotation members may be of light, strong sheet metal construction and may be faced with rubber-like material to decrease adhesion to snow or ice and'to reduce wear of the flotation members. 4They are relatively wide as compared to the span of the bands which support them and the track may be used with driving and supporting gear that need not be of great width but may have the protection afforded by occupation of only a relatively narrow zone in the'center of the track. Other flexible tension members may be provided laterally of the load supporting bands and connected to the flotation members, providing `vadditional lateral stability, especially stability of the track against lateral twisting and bending.

Referring to Figs. l to 5 of the drawings, the numeral I0 designates the body of a vehicle having a drive shaft II, to which are secured drive sprockets such as I2, I2. The weight cf the vehicle is supported by bogie wheels such as I3,v I3 which bear upon tracks I4, I 5 trained about the drive sprockets and the bogie wheels.

The tracks I4, I5 are alike and only one need be described, as follows: A pair of flexible bands I6, I1 of resilient rubber or other rubber-like material, are provided for contacting with the treads of the bogie wheels. Extending through each band in laterally spaced-apart relation are tension elements or members I8, preferably in the form of flexible metal cables, or convolutions of the same cable, to which the rubber-like material is secured as by a bond of vulcanization. Also partially embedded in the resilient material ofthe bands are complementaryvpairs of cross straps I9, 20 at spaced-apart intervals longitudinally of the track. Straps 2li are preferably flat, whereas strapsv I9 are preferablyl bent or offset near their ends and beyond the reinforcing cables. The arrangement is such that members extend surrounded b' rubber-like cushioning material, while the ends f the straps 'I'hese members are preferably formed of sheet metal and provide a raised guide 21 and a plurality of apertured ears 26, 26, 3l, 3| adapted to be secured to the ears 25, of a plurality of cross straps at each side of the connecting members. The fore and aft margins of ears 2,6, 29, 30, 3i adjacent sprocket` tooth openings 41 may be turned downwardly to provide driving faces 32l for engaging the teeth of the driving sprocket for driving the track. The connecting members are secured to the bands I6, I1 as by rivets 33, 34. The ends of the ears 26, 29, 30, 3i away from the sprocket teeth openings 41 are preferably extended as platforms 32a which may be in relatively close proximity so as to prevent sprocket teeth from entering anywhere except in the openings 41, and owing to the locations of these platforms approximately in the pitch line, flexure of the track does not cause interference of these platforms.

For supporting the track and the vehicle on snow, sand, or soft mud, or other owable material, shoes 40 of broad area, preferably of sheet metal, are provided. These shoes extend a considerable distance laterally beyond the bandsr I6, I1 to provide supporting wings 42, 43 having upwardly turned tips 44, 45 toi facilitate turns on soft snow. To strengthen the shoes the material thereof is formed with ribs or corrugations 46 extending in a. direction crosswise of the track. Openings 41 for escape of snow, soil`or other material are provided in the shoes .between the bands I6 and I1. Slots 40a may.` be provided in the tips of the shoes to secure removable grousers, if desired.

For additionally strengthening the shoes, and to provide grousers for increasing traction, transversely extending cleats 50 of'metal are secured to the tread faces of the shoes, as by welding. These cleats may also be made of sheet metal and, to provide great strength in the direction of travel, are each formed of strips 5I, 52 of generally angular cross-section welded or otherwise secured to each other back to back.

'I'o provide resistance to adhesion of snow and ice and to provide greater resistance to abrasion,

the shoes 46 may be provided on their tread faces with a layer B of resilient rubber orother rubberlike material bonded or otherwise' secured to the metal. The cleats may be provided with surface coverings 6 I, 62 of resilient material for the same purpose. The edges of the cleats 50 are, however, preferably exposed as at 63 and the angle pieces I, 52 may be arranged to provide a stepped edge as shown to provide a relatively sharp biting edge of metal to grip surfaces such as ice. For providing additional -strength thereto, the metal providing the sides of the guides 21 may be welded together along the forward and rearward edges 64, 65 of the sides.

The track is particularly light in weight while providing a greatv area for ground contact protherebetween through which the tensionv 4 viding high notation on snow, sand, mud, or other flowable material. At the same time noise isreduced and cushioning provided by the rubber covered bands I6, I1 vwhich provide resilient tracks for the bogie wheels. The assembled construction greatly facilitates manufacture and makes possible conservation of materials.

In the modification shown in Figs. 6 to 9 of the drawings, the numerals 10, 1I designate a pair of flexible bands of resilient rubber or other rubber-like material, similar to the bands I6, I1 of the track of Fig. 2, for contacting with the treads of the bogie wheels. Extending through each band in laterally spaced-apart relation are tension elements or members 12, preferably in the form of flexible metal cables or convolutions of the same cable, to which the rubber-like material is secured as by a bond of vulcanization. Also partially embedded in the resilient material of the bands are complementary pairs of cross straps 13, 14 at spaced-apart intervals longitudiby rivets B I.

nally of the track. Straps 14 are preferably flat, whereas straps 13 are bent or oset near their ends and beyond the reinforcing cables. The

' arrangement is such that each pair of straps 13,

14 defines a single space 15 therebetween through which the tension members extend surrounded by rubber-like cushioning material, while the end of the straps extend at the sides of the band in superimposed relation to provide longitudinally spaced-apart apertured fastening ears by which the band may be assembled with and attached to other parts of the track.

For holding the bands 10, 1I in spaced-apart relation and to provide guiding and driving means for the track, bearing blocks 16 of hardcned steel span the space between the inwardly directed ears of the straps 13, 14 and have a rounded margin 16a transverse of the .track for contacting the sprocket teeth of the driving sprocket? Above the bearing blocks and the ears y of the straps overlapping them, connecting and guiding members 11 are provided. Each connecting and guiding member 11 is formed of sheet metal to provide an upstanding guide member 16 intermediatethe bands. Each connecting and guiding member longitudinally spans two of the bearing blocks and has longitudinally spacedapart ears 19, at each side of its guide member which each overlap the ears of the cross strap and the bearing blocks and are secured thereto At their fore and aft margins, the connecting and guiding members extend as platforms 19a, 80a which closely approach 'each other so as to prevent the entrance of a drive sprocket tooth therebetween, while at the centers of the connecting and guiding members an opening 82 is provided between the ears at each side of the guiding member to receive the sprocket teeth.

Thus, the sprocket teeth are compelled to reenter their assigned openings in case of jumping. If desired, the platforms 19a, 80a may be curved as shown in Fig. '7 for added strength. As these platforms are located approximately in the pitch line of the track they do not interfere with one another upon iexure of the track.

For supporting the track and the vehicle on snow, sand, soft mud, or other readily flowable material, shoes 85 of broad area, preferably of light weight and sheet metal, are provided. These shoes extend a considerable distance laterally beyond the bands, 10, 1I to provide supporting wings 86, 81 having upwardly turned tips to facilitate making turns on soft snow.

To strengthen the shoes, each is formed with a deep laterally extending corrugation 88 midway of its fore and aft margins providing lateral stiffness. For additionally strengthening the shoes andproviding traction on soft ground, a cleat 90 is formed of angle sections 9|, 92 of sheet metal arranged back to back and welded to each other and to the shoe with their projecting edges offset or in stepped relation as shown in Fig. 3 so as to form a sharp cross cleat at the center of each shoe.

For providing a tread surface capable of supporting the shoes against tipping due to line contact with the ground, the sheet metal pieces which provide the angle sections 9|, 92 are formed with box-like extensions 93, 94 fore and aft of the cleat 90 and beneath the bands 10, 1|, connected by a web 95 through which rivets 8| are secured. Cushion treads 96, 91 are secured to the metal as by a bond of vulcanization for providing a substantially fiat contact with the ground and preventing rocking of the shoe.

'Ihe material of the shoes is formed with apertures 98 for clearing the sprocket teeth and the margin about each aperture is strengthened by a surrounding downwardly turned flange 99.

To provide resistance to adhesion of snow and ice and to provide greater resistance to abrasion the shoes 85 and the cleats 90 may be provided on their tread faces with surface coverings |00,

|0|, |02, |03 of resilient rubber or other rubberlike material having a low adhesion to ice and secured to the metal preferably by a bond of vulcanization. The edges of the cleats are also similarly protected but the covering soon wears -through at the sharp edges of the cleats to provide a sharp biting edge of metal to grip surfaces such as ice, or if desired the edges may be exposed initially. The edges are preferably formed with `portions |04, |05 which project below the remainder of the cleat edge to provide calks for entering the ice.

Referring to the modified form of the invention illustrated in Figs. 10 to 14 of the drawings, longitudinally-extending flexible bands |25, |26 of resilient rubber or other rubber-like material, similar to bands I6, l1 of the track of Fig. 2 are provided in spaced-apart relation for contacting the treads of the load supporting bogie wheels and also the driving wheels |21, |28. Sprockets |21a, I28a are secured to the driving wheels |21, |28 in a position to clear the bands and guide members and to engage the bearing blocks of the shoes, hereinafter described. Extending through each band in laterally spaced-apart relation are tension elements or members |29 extending in straight parallel reaches, preferably in the form of flexible metal cables or convolutions of the same cable, to which the rubber-like material is secured, as by a bond of vulcanization. Also partially embedded in the resilient material of the bands are complementary pairs of cross straps |30, |3| at spaced-apart intervals longitudinally of the track. Straps |30 are preferably flat, whereas straps |3| are bent or offset near their ends and beyond the reinforcing cables. The arrangement is such that each pair of straps |30, |3| denes a single space |32 therebetween through which the tension members extend surrounded by rubber-like cushioning material, while the ends of the straps extend at the sides ofl the band in superimposed relation to provide longitudinally spaced-apart apertured fastening ears by which the band may be assembled with and attached to other parts of the track.

For holding the bands |30, |3| in spaced-apart relation and to provide guiding and driving means for the track, bearing blocks |40 of hard metal, such as hardened steel, span the space between the inwardly directed ears of the straps |30, |3| and have arounded margin |40a transverse of the track for contacting the sprocket teeth |4|. The bearing blocks |40 are located in spaced-apart relation longitudinally of the track so that the teeth |4| may enter therebetween. Above the bearing blocks and the ears of the straps over-lapping them, connecting and guiding members |42 are provided. Each connecting and guiding member |42 is formed of sheet metal to provide a seamless upstanding guiding member |43 intermediate the bands. Each connecting and guiding member longitudinally spans two of the bearing blocks and has longitudinally spaced-apart footings |44, |45 each of which transversely spans adjacent ears of strap members |30, |3| over the bearing blocks and is secured thereto by rivets |46. The footings of successive guide members are formed with extensions |41, |48 which bridge the space between the successive bearing blocks to which they are respectively secured in side by side relation, the extensions being nonsymmetrically disposed as to the centerline of the track to break joints. The footings of each guide member are spaced apart longitudinally of the track to provide spaces therebetween` for receiving the sprocket teeth |4|. Thus the sprocket teeth are compelled by the arrangement of footings to reenter their assigned openings in case of jumping. If desired the footings may be curled at their fore and aft margins, as at |49 for added strength. As these margins are located approximately at the pitch line of the track they do not interfere with one another upon flexure of the track.

For supporting the trackand the vehicle on snow, sand, soft mud, or other readily owable material, shoes |55 of broad area, preferably of light sheet metal, are provided. These shoes extend a considerable distance laterally beyond the bands |25, |26-to provide supporting wings |56, |51 having upwardly turned tips to facilitate making turns on soft material.

To strengthen the shoes, each is formed with a deep laterally extending corrugation |58 midway of its fore and aft margins providing lateral stiiness. For additional strengthening of the shoes and providing traction on soft ground, a cleat |59 isformed of angle sections |60, |6I of sheet metal arranged back to back and welded to each other and to the shoe laterally of the track so as to form a sharp cross cleat at the center of each shoe.

For providing a tread surface capable of supporting the shoes against slipping due to line contact with the ground, the sheet metal pieces which provide the angle sections |60, |6| are formed with box-like extensions |65, |66 fore and aft of the cleat |59 and beneath the bands |25,"

|26 connected by a web |61 through which the rivets |46 are secured. Cushion treads |68, |66 are securedto the metal as by a bond of vulcanization for providing a substantially flat contact with the ground and preventing rocking of the shoes.

The material of the shoes is formed with apertures |10 for clearing the sprocketteeth |4| and the margin about each aperture is strengthened by a surrounding downwardly turned ange |1|.

To provide additional lateral stability to the wings |56, |51 ofthe shoes and to reduce tor- 7 sional distortion of the track and to distribute locally applied :loads while maintaining longitudinai flexibility of the track, longitudinally disposed flexible tension members |15, |16 are arranged near the tips of the wings and secured to each wing. These may each be like the member |25, in the form of a group of laterally spacedapart tension elements |11, such as Wire cables or convolutions of the same cable embedded in a strip |18 of rubber or other rubber-like resilient material. The cables are enclosed in a bight formed between pairs of strap members |19. |80 located at longitudinally spaced-apart intervals, as in the strips |25. The straps |19 are straight whereas the straps |80 are bent or offset to provide the bight enclosing the tension members. The straps extend laterally beyond the strip |18 to provide superimposed lateral ears having apertures whereby they are secured to the Wings of the shoes by rivets |8I, |812. 'I'he tension elements serve to hinge the shoes to each other near their tips and to distribute the load on a shoe to adjacent shoes, thereby providing greater stability.

To provide resistance to adhesion of snow and ice and to provide vgreater resistance to abrasion, the shoes and the cleats with surface coverings |85, |86, |81 of resilient rubber or other rubberlike material having a low adhesion to ice are secured to the metal preferably by a bond of vulcanizaton. 'I'he edges of the cleats are also similarly protected but the covering soon wears through at the sharp edges of the cleats to provide a sharp biting edge of metal to grip surfaces such as ice, or if desired the edges may be exposed initially. The edges are preferably formed with portions |88, |89 which project below the remainder of the cleat edge: to provide calks for entering the ice.

Variations may be made without departing from the scope of the invention as it is defined by the following claims.

I claim:

1. A track for self-laying track type vehicles, said track comprising a plurality of separate parallel exible bands constituting individual units each comprising longitudinally disposed tension elements embedded in rubber-like material, cross straps individual to a band and associated with the tension `elements extending laterally through the band and providing attaching portions at its sides, the -attaching portions of the cross straps of one band being spaced laterally of the track from the attaching portions of an adjacent band, and means secured to said portions of said straps connecting said bands in laterally spaced-apart relation for separate removal and replacement.

2. A track for self-laying track type Vehicles, said track comprising a pair of separate parallel flexible bands constituting individual units each comprising longitudinally disposed tension elements embedded in rubber-like material, cross straps individual to a band and separated from said tension elements by the rubber-like material and secured to the rubber-like material and extending laterally through the band and providing attaching portions at its sides, the attaching portions of the cross straps of one band being spaced laterally of the track from the attaching portions of an adjacent band, and means secured to said portions of said straps connecting said bands in laterally spaced-apart relation for separate removal and replacement.

3. A track for self-laying track type vehicles,

said track comprising a pair of separate parallel flexible bands constituting individual units each comprising longitudinally disposed tension elements embedded in rubber-like material, cross straps individual to a band extending laterally through the band and providing attaching portions at its sides, the attaching portions of the cross straps of one band being spaced laterally o! the track from the attaching portion of an adjacent band, and means secured to said portions of said straps connecting said bands in laterally spaced-apart relation for separate removal and replacement said connecting means having surfaces for engaging a track-driving sprocket.

4. A track for self-laying track type vehicles, said track comprising a pair of separate parallel ilexible bands constituting individual units each comprising longitudinally disposed tension members embedded in rubber-like material, cross straps individual to a band extending laterally through the band and providing attaching portions atv its sides, the attaching portions of the cross straps of one band being spaced laterally of the track from the attaching portion of an adjacent band, and means secured to said portions of said straps forconnecting said bands in laterally spaced-apart relation for separate removal and replacement said connecting means having a surface for engaging a track-guiding wheel.

5. A track for self-laying track type vehicles, said track comprising a plurality of separate parallel flexible bands constituting individual units each comprising longitudinally disposed tension elements embedded in rubber-like material, cross straps individual to a band extending laterally through the band and providing attaching portions at its sides, the attaching portion of the cross straps of one band being spaced laterally of the track from the attaching portion of an adjacent band, and means secured to said portions of adjacent bands for connecting them in laterally spaced-apart relation for separate removal and replacement said connecting means comprising a ground-engaging shoe.

6. A track for self-laying track type vehicles, said track comprising a plurality of separate parallel flexible bands constituting individual units each comprising longitudinally disposed tension elements embedded in rubber-like material, cross straps individual to alband extending laterally through the band and providing attaching portions at its sides, the attaching portions of the cross straps of one band being spaced laterally of the track from the attaching portion of an adjacent band, and means secured to said portions of adjacent bands for connecting them in laterally spaced-apart relation for separate removal and replacement said connecting means comprising a tread shoe, and said shoe having a ground-engaging cross cleat.

7. A track for self-laying track type vehicles, said track comprising a plurality of separate parallel flexible bands constituting individual units each comprising longitudinally disposed tension elements embedded in rubber-like material, cross straps individual to a band extending laterally through the band and providing attaching ears at its sides, the attaching portions of the cross straps of one band being spaced laterally of the track from the attaching portion of an adjacent band, and means secured to the ears of adjacent bands for connecting them in laterally spaced-apart relation for separate removal and replacementsaid connecting means accgooe comprising a driving and guiding member secured to ears of adjacent bands and bridging the space therebetween.

8. A track for self-laying track type vehicles, said track comprising a plurality of separate parallel flexible bands constituting individual units each comprising longitudinally disposed tension elements embedded in rubber-like material, cross straps individual to a band extending laterally through the band and providing attaching ears' at its sides, the attaching portions of the cross straps of one band being spaced laterally of the track from the attaching portion of an adjacent band, and means secured to the ears of adjacent bands for connecting them in laterally spacedapart relation for separate removal and replacement, said connecting means comprising a driving and guiding member secured to ears of adjacent bands and bridging the space therebetw'een, and a relatively wide sheet metal tread shoe secured to ears at the outer margins of the bands and extending therebeyond.

9. A track for a self-laying track type vehicle, said track comprising a plurality of laterally spaced-apart tension elements, a longitudinal series of cross structures each comprising a pair of cross members having faces opposing said tension elements, said faces being spaced from'said tension elements and at least one of said faces being substantially even across said tension elements, and a body of resilient rubber-like material surrounding and separating said elements and iilling the space between and secured to said elements and said faces, said -cross members having attaching portions extending laterally beyond the sides of said body.

10. A track for a self-laying track type vehicle, said track comprising a plurality of laterally spaced-apart tension elements, a longitudinal series of cross structures each comprising a pair of cross plates having faces substantially at across said'tension elements and opposing said tension elements in spaced relation thereto, and a body of resilient rubber-like material surrounding and separating said elements and lling the space between and secured to said elements and said faces, at least one of the cross plates of the pair being bent into juxtaposition with the other plate to provide attaching portions extending laterally beyond the sideslof said body.

11. A track for a self-laying track type vehicle, said track comprising a longitudinally extending tension structure, and a plurality of tread elements secured to said tension structure, said tread elements each comprising sheet metal having an extensive ground-contacting face and cleats thereon presenting ice-gripping edges, and a layer of rubber-like material secured to said sheet metal on said face and said cleats leaving said edges of the metal exposed.

12. A track as defined in claim 11 in which the lateral margins of each of said tread elements are bent obliquely away from said face.

13. A track as dened in claim 11 in which the ice-gripping edges of said cleats are provided by oilset edges of sheet metal parts secured together with their edges in stepped relation.

14. A track for a self-laying track-type vehicle, said track comprising a pair of laterally spaced-apart driving bands, each of said bands comprising a longitudinal series of cross structures individual to a band each comprising a pair of cross plates having faces opposing each other in spaced-apart relation, a plurality of laterally spaced-apart tension elements disposed between said faces Vin spaced relation thereto, said faces being substantially even across said tension ele- .ments, a body of rubber-like material separating said tension elements from each other and from said faces, said cross plates having attaching portions at the sides of said bodies, tread members each extending across said bands, and means for securing said tread members to said attaching portions of the cross members.

15. A track for self-laying track-type vehicles, said track comprising a longitudinally extending tension-resisting structure'including a series of l plates and having a series of openings for receiving sprocket teeth, adjacent ends of said plates being in such close proximity as to prevent entrance between them of the sprocket teeth.

16. A track lfor self-laying track-type vehicles, said track comprising a flexible band structure comprising longitudinally extending tension elements, cross structures secured to said tension elements, and guide plates secured to said cross structures, said band structure having openings for receiving sprocket teeth, said guide plates having ends in such close proximity one to another as to prevent the entrance between them of the sprocket'teeth, and said ends being approximately at the pitch line of said tension elements.

17. A track for self-laying track type vehicles, said track comprising a plurality of separate parallel flexible bands each comprising longitudinally disposed tension-resisting elements embedded in. rubber-like material, cross straps individual to a bandM and associated with the tension-resisting lements extending laterally through the band and providing attaching portions at its sides, shoes secured to said portions of said straps connecting said bands in laterally spaced-apart relation, said bands providing a track for load-supporting wheels of the vehicle, and flexible tension-resisting members arranged parallel to said bands and secured to said shoes at positions spaced laterally outward from said bands.

18. A track for a self-laying track type vehicle, said track comprising `a flexible band structure of rubber-like material extending longitudinally of the track and having tension-resisting means embedded therein, a longitudinal series of cross members secured to said band structure and having end portions extending laterally thereof, and longitudinally extending iiexible elements secured to said cross members at positions spaced laterally outward from said band structure.

19. A track for a self-laying track type Vehicle, said track comprising a flexible band structure extending longitudinally of the track, said band structure comprising a body of rubber-like material having tension-resisting cable means embedded therein and cross straps individual to said band structure embedded therein and having attaching portions extending at the sides of said band structure, a longitudinal series of cross members secured to said attaching portions of said band structure and having end portions extending laterally of said band structure, and 1ongitudinally extending exible elements secured to said cross members at positions spaced laterally outward from said band structure and beyond said attaching portions.

20. A track for a self-laying track type vehicle, said track comprising a longitudinal series of shoes each disposed cross-wise of the track. a 

